A biopsy entails the surgical removal of tissue or cells from the body of a patient for pathological examination of the collected sample. The purpose for taking a biopsy sample is often to look for cellular shape changes represented in the collected sample. The identification of particular cellular shape changes in a collected specimen can be instrumental in the identification of cancer in a patient.
Endoscopes are often used to access and visualize a patient's anatomical lumen during a medical procedure. Once the endoscope is positioned in the desired body portion, a biopsy instrument can be advanced through the working channel of the endoscope to the desired body portion. The endoscopic and biopsy instruments may then be manipulated as desired for visualization and specimen sampling respectively.
Smaller diameter endoscopes are presently available in the endoscopy market that help reduce unnecessary trauma to the tissues of a patient and provide more versatile endoscopes capable of accessing more diverse categories of patient body lumens. Smaller diameter endoscopes often have smaller working channels, which limit the size of any auxiliary instrument used. This, in turn, limits the size, and often the quality of, any biopsy specimen collected.
Presently, several biopsy techniques (e.g., pinch biopsy, needle biopsy, and cytology brush) are used to obtain a biopsy specimen.
In general, a pinch biopsy is performed by a biopsy instrument having forceps with two jaws activated by an internal manipulating wire or wires. The instrument is passed through an endoscope to a desired location, and then the jaws are opened and closed to grab and sever the biopsy sample. The instrument with the detached sample is then withdrawn from the endoscope so that the sample is removed. If another biopsy specimen is needed, the forceps is then re-inserted into the endoscope and relocated for the next biopsy. Frequently, due to a small moment arm of the instrument, the cutting force of the jaws is not sufficient or the jaws are not sharp enough to cleanly shear the tissue which is then torn off by a pulling movement. In addition, such biopsy instruments may be too large for smaller diameter endoscopes with smaller diameter working channels.
A needle biopsy is usually performed with a two part device. The first part includes a stylet-needle shaft having a tissue retaining recess formed in a lateral side of the area close to the needle tip. When the needle is inserted into tissue from which a sample is desired, a portion of tissue extends into the recess. The second part typically includes an outer sheath, or cannula, that is fitted over the needle shaft and includes a blade formed at a distal end to cut off and encapsulate the tissue retained in the needle shaft recess. Such needle biopsy devices often cannot be positioned in flexible small diameter positioning devices because the puncturing stylet-needle is rigid.
To collect cells for cytological examination, a distal brush device is passed through an endoscope to a collection site. The brush is extended from its sheath and, by brushing the tissue, the cells are scraped and collected onto the bristles. The brush is retracted into the sheath to prevent decontamination, the instrument is withdrawn from the body, and the cells are deposited on glass slides for review. However, the brush can collect only tissue cells, which is often not sufficient since tissue samples are required for many histopathological evaluations.
In many situations, it is desirable to collect multiple biopsy specimens from the same location or several precisely defined locations. For example, when examining the spread of the diseased tissue, multiple biopsies are taken from several sites spread apart. In this process, if a biopsy instrument capable of collecting only a single specimen is used, the instrument must be withdrawn from the patient to remove the collected biopsy specimen before the next specimen can be taken. This substantially lengthens the biopsy process. For a subsequent biopsy, the physician has to re-insert and re-orient the biopsy instrument in relation to the subsequent biopsy site. The re-orientation may be quite difficult and time consuming since the biopsy instruments are often 200 cm long. The time delay may cause a fatigue of the medical team, requires a longer sedation time of the patient, and could also negatively affect the number and quality of the specimens which, in turn, could negatively influence the diagnosis.
Thus, it is desirable to have an alternative flexible, low profile biopsy device that can access small working channels of smaller endoscopic devices and obtain multiple large tissue samples adequate for pathology study.